BIOCHEMICAL CHARACTERIZATION OF FREE AND IMMOBILIZED α–AMYLASE FROM ASPERGILLUS NIGER AND ITS BIOTECHNOLOGICAL APPLICATIONSAbstract
α-amylase is widely used in various biotechnological applications such as food processing, starch, and paper industries, hydrolyzing starch, glycogen, and other polysaccharides into glucose, maltose, and oligosaccharides. Aspergillus niger α-amylase was partially purified by ammonium sulphate fractionation with 1.409 fold purity and 54.88% yield. The partially purified α-amylase was immobilized on sodium alginate with calcium chloride by ionotropic gelation with glutaraldehyde as a cross-linking agent. Immobilized α-amylase exhibited 50% of its original activity. The soluble and immobilized α-amylases exhibited maximum activity at pH values 7.5 and 8.0, respectively. The optimum temperature for both the soluble and immobilized enzymes was 35 ºC. The immobilized enzyme was more pH and thermally stable than the soluble one. The substrate starch was hydrolyzed by soluble (Km 0.6 mg/ml, Vmax 16.05 mg/ml/min) and immobilized α-amylase (Km 0.65 mg/ml, Vmax 17.41 mg/ml/min) with high efficiencies. On the basis of the results obtained, immobilized α-amylase could be employed in the saccharification of starch processing.
N. Kote *, A. C. Manjula, T. Vishwanatha and E. Keshamma
Department of Biochemistry, Maharani’s Science College for Women, Bengaluru, Karnataka, India.
31 May 2019
21 August 2019
19 March 2020
01 April 2020